They were inspired by the #MatchForLara campaign that went viral and helped find a donor for another young woman from a mixed-race background.

Image copyrightTwitter

Zara, from Winchester, Hampshire, opened the Match4Zara account with her father Loua Al Shaikh last week.

He told BBC News: "We thought we had nothing to lose by giving this a try. We put the first tweet out and the notifications on my mobile phone haven't stopped.

"I had a Twitter account but I've never used it. I was amazed at the response we've had from all over the world."

Among those who retweeted the appeal were Sherlock actors Mark Gatiss and Louise Brealey as well as American author Rainbow Rowell.

People have started replying saying they will register to see if they could be a donor, including people from mixed heritage.

"It gives us hope and shows Zara that she is not alone."

Image copyrightTwitter

Zara faces the problem highlighted by the viral #Match4Lara campaign, started by 24-year-old Lara Casalotti who is of Thai and Italian heritage.

It is harder for people with mixed-race backgrounds to find donors because they have rarer tissue types and there are relatively few people of ethnic minority backgrounds registered as donors.

This is partly because of a lack of awareness, says Loua Al Shaikh - who is also a doctor. There is also a myth that the procedure for donation is complicated, when in fact it is quite simple, he says.

As well as the Twitter account, there is a Facebook account called Saving Zara and other family members are setting up a campaign website.

Dr Al Shaikh says he hopes he can get more people registering as possible donors, whatever background they have.

"The more people who register, the higher chance for all waiting for a transplant to find their donor match.

"It's sad to say, but no-one knows when you or someone you love might need that help."